Genome-Wide Identification and Functional Exploration of SBP-Box Gene Family in Black Pepper (Piper nigrum L.)

Genome-Wide Identification and Expression Analysis of the SBP-Box Gene Family in Loquat Fruit Development

The loquat (Eriobotrya japonica L.) is a special evergreen tree, and its fruit is of high medical and health value as well as having stable market demand around the world. In recent years, research on the accumulation of nutrients in loquat fruit, such as carotenoids, flavonoids, and terpenoids, has become a hotspot. The SBP-box gene family encodes transcription factors involved in plant growth and development. However, there has been no report on the SBP-box gene family in the loquat genome and their functions in carotenoid biosynthesis and fruit ripening. In this study, we identified 28 EjSBP genes in the loquat genome, which were unevenly distributed on 12 chromosomes. We also systematically investigated the phylogenetic relationship, collinearity, gene structure, conserved motifs, and cis-elements of EjSBP proteins. Most EjSBP genes showed high expression in the root, stem, leaf, and inflorescence, while only five EjSBP genes were highly expressed in the fruit. Gene expression analysis revealed eight differentially expressed EjSBP genes between yellow- and white-fleshed fruits, suggesting that the EjSBP genes play important roles in loquat fruit development at the breaker stage. Notably, EjSBP01 and EjSBP19 exhibited completely opposite expression patterns between white- and yellow-fleshed fruits during fruit development, and showed a close relationship with SlCnr involved in carotenoid biosynthesis and fruit ripening, indicating that these two genes may participate in the synthesis and accumulation of carotenoids in loquat fruit. In summary, this study provides comprehensive information about the SBP-box gene family in the loquat, and identified two EjSBP genes as candidates involved in carotenoid synthesis and accumulation during loquat fruit development.

Identification and screening of fungicides against Piper nigrum basal Fusarium wilt disease in Hainan, China

Fusarium wilt has occurred in the main Piper nigrum cultivation regions, which seriously affects the yield and quality of P. nigrum. To identify the pathogen of this disease, the diseased roots were collected from a demonstration base in Hainan Province. The pathogen was obtained by tissue isolation method and confirmed by pathogenicity test. Based on the morphological observation, sequence analyses of TEF1-α nuclear gene, Fusarium solani was identified as the pathogen causing P. nigrum Fusarium wilt and induced symptoms on inoculated plants, including chlorosis, necrotic spots, wilt, drying, and root rot. The experiments for the antifungal activity showed that all the 11 fungicides selected in this study showed certain inhibitory effects on the colony growth of F. solani, where 2% kasugamycin AS, 45% prochloraz EW, 25 g·L-1 fludioxonil SC and 430 g·L-1 tebuconazole SC exhibited relative higher inhibitory effects with EC50 as 0.065, 0.205, 0.395, and 0.483 mg·L-1 , respectively, and were selected to perform SEM analysis and test in seeds in vitro. The SEM analysis showed that kasugamycin, prochloraz, fludioxonil, and tebuconazole might have exerted their antifungal effect by damaging F. solani mycelia or microconidia. These preparations were applied as a seed coating of P. nigrum Reyin-1. The kasugamycin treatment was most effective in reducing the harmful impact of F. solani on the seed germination. These results presented herein provide useful guidance for the effective control of P. nigrum Fusarium wilt.